Not Applicable
This application includes a computer program listing appendix submitted on a compact disc. The listing resides in an ASCII text file entitle xe2x80x9cCD_ALL.TXTxe2x80x9d, size 35 Kbytes, created May 10, 2001. The contents of this computer program listing are incorporated in this application by reference.
The present invention is related to the field of data mining, and in particular to tools for automating the collection, analysis, and presentation of data such as manufacturing process control data.
Tools for collecting, storing and retrieving data pertaining to manufacturing processes have been known. In the semiconductor industry, for example, a tool known by the trade mark PROMIS has been used for different manufacturing-related data. In particular, PROMIS has been used to track so-called xe2x80x9ccritical dimensionxe2x80x9d or CD data, which results from measurement of critical dimensions such as line widths on wafers and die before and after various processing steps. Process engineers and others use this information to monitor and tune manufacturing processes for proper performance.
Additionally, other tools have existed for performing analysis of the type of data that has been gathered by tools such as PROMIS. Of particular use in a manufacturing operation are tools for statistical process control. One widely used statistical analysis tool is known by the acronym SAS, which stands for Statistical Analysis Software. SAS includes functionality enabling it to perform very sophisticated analysis that is specialized to statistical studies.
PROMIS can be characterized as a xe2x80x9clegacyxe2x80x9d application, due to its longevity and original deployment on minicomputers such as those previously sold by Digital Equipment Corporation, formerly of Maynard, Mass., USA. The application software and database reside on a centralized general-purpose computer, such as an ALPHAServer sold by Compaq Computer Corp. of Houston, Tex., USA, and user interfaces are placed throughout the manufacturing facility. Technicians operating manufacturing equipment are responsible for obtaining critical dimension measurements and/or other data from material processed in respective work centers and inputting the information into the PROMIS system so as to be available to the process engineers or other personnel associated with the processes.
SAS, on the other hand, is more commonly run on a workstation or personal computer. The data to be analyzed must be stored in the workstation by some means so as to be available for SAS analysis. From the data, SAS generates charts and other forms of outputs to aid a user in understanding the characteristics of the data.
It has been known to use workstation-based applications such as SAS in conjunction with legacy data-collection applications such as PROMIS. The basic operation has been to invoke PROMIS to extract desired data and then invoke SAS to perform a desired analysis on the data and present the results in a desired fashion. The overall process has been cumbersome and inefficient. A user is required to engage in rote dialog with PROMIS to perform the data extraction, manually copy the data from the server to the SAS workstation, perform any necessary file conversions, and invoke SAS in the correct manner to do the desired analysis and presentation. The entire process must be performed for each data set of interest. In a facility such as a semiconductor manufacturing plant, a large number of different processes and associated equipment must be tracked daily just to obtain routine analyses and charts. It is therefore desirable that alternative, more efficient, methods of performing these functions be found.
In accordance with the present invention, methods and apparatus for gathering statistical process control (SPC) information for manufacturing processes and presenting the SPC information to personnel responsible for the manufacturing processes are disclosed. The techniques are flexible and yet highly automated, enhancing the ease and efficiency of their use. Additionally, the SPC information is presented to users in an easy-to-use, hypertext-based form, enabling the users to make even more effective use of the time spent reviewing the gathered data.
The system employs a process information system and an analysis information system. In one embodiment, the process information system includes ALPHAServer computers running the VMS operating system and PROMIS application software, while the analysis information system includes one or more UNIX workstations and SAS application software.
In the analysis information system, a command file is generated including (i) a command for invoking a process data extraction program such as PROMIS using the contents of a script file as input, and (ii) a command for copying an extracted data file generated by the process data extraction program to the analysis information system. Additionally, the script file for use by the process data extraction program is generated. The script file includes a predetermined set of responses to command-line queries automatically generated by the process data extraction program upon its invocation. The information system then issues a command to the process information system indicating that an extraction command routine is to be executed.
The process information system responds to the command by executing the extraction command routine, which routine includes (i) copying the command file from the analysis information system to the process information system, and (ii) executing the command file. This processing results in an extracted data file containing the desired raw data.
After the process information system has completed the data extraction, the analysis information system performs statistical analysis on the extracted data file. Then, for each of several statistical parameters generated by the statistical analysis, a corresponding graphical SPC chart file is created based on the associated data from the statistical analysis. A hypertext summary of the SPC chart files, including hyperlinks thereto, is also created. The graphical SPC chart files and hypertext summaries are then posted in a network-accessible database so as to be easily viewable by the process engineers or other personnel responsible for the manufacturing processes. The overall procedure is repeated for each distinct manufacturing process or work center.
Due to the highly automated nature of the disclosed techniques, a large quantity of process-related data can be collected, analyzed and presented to users with a minimum of human involvement, improving the efficiency and effectiveness of the manufacturing operation.
Other aspects, features, and advantages of the present invention are disclosed in the detailed description that follows.